The Role of Chemical Composition of Leaded Bronze Alloy in Deterioration Process, Applied on Some Archaeological Statues from Dhamar Museum, Yemen

This study aims to gain further insight into the surface features of five leaded bronze from Dhamar museum, Yemen, to know the role of chemical composition in deterioration process, identify the ancient manufacturing processes, which were used to produce the statues, to get a deeper in sight into the morphology and mineralogy of corrosion products, the cause and mechanism of corrosion process to control it and to identify the types of corrosion products of selected objects as well as their constituting metals in order to carry out scientific treatment and conservation to avoid the further deterioration. To achieve that the selected objects have been studied by means of the combined use of metallographic microscope, scanning electron microscopy combined with energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD) techniques. Metallographic examination results indicated a non-homogenous structure, localized corrosion spots and the existence of lead islands in the alloy, scanning electron microscope examination showed the microstructure for the grains and aspects of deterioration, it confirms metallographic examination results. The chemical composition analysis declared that the statues are made of leaded bronze alloy. The patina of the examined objects were consisted of two layers and composed of Cuprite, Atacamite, Quartez. Finally the obtained results helped us in treatment and conservation the selected objects.